Design of a permanent-magnet, synchronous and limited-angle torque motor for a rotary spool valve

This thesis dissertation focuses on the design of a limited angle torque motor able to drive and control a spool valve of a fully active suspension system for automotive applications. Such a system can work as passive and semi-active dampers, absorbing and dissipating energy from the interaction between road and vehicle, but it is also able to introduce energy in the equation above. This allow the car to achieve greater results in terms of both handling and comfort. An example of handling improvement is the reduction and eventually the elimination of the roll rotation of the chassis of the vehicle during the various stages of a curve, while, regarding the comfort, in case of bump or hole in the path of a wheel, this system could actively pull up or push down the hub of the wheel, smoothing the effect of a change in the road to body of the automobile. The motor designed in this paper is en electric motor, with permanent magnets mounted on the surface of the rotor and windings supplied by a direct current wound around the stator. The state on the art of this kind of motor is not large, because of their narrow window of possible applications, so this dissertation aims at developing a possible solution for suspension problem without the use of a 3-phase excitation and also at exploring more in deep this category of torquers, with the possibility of reevaluating and putting them in a better light. The geometry of the motor is drawn in parametric form to ease the future changes and to keep flexibility to other modifications. Then the dimensions are optimized with the particle swarm algorithm, in order to find the best solutions in terms of torque capability, without exceeding the limitations due to space and to maximum flux that the ferromagnetic cores can withstand. The project did not lead to a successful result for the suspension application but, not only it presents a thorough study of the literature of limited angle motors and optimization algorithms, but also shows a flexible MatLab script to design a new limited angle torquer for different applications and with new dimensions.